This Week in Blockchain Research Issue #95

Issue #95

Issue #95

Paper of the Week:

Paper Title: The Bitcoin Cash Backbone Protocol.


  1. Bitcoin Cash, created in 2017, is a “hard fork” from Bitcoin responding to the need for allowing a higher transaction volume. This is achieved by a larger block size, as well as a new difficulty adjustment (target recalculation) function(s) that acts more frequently (as opposed to Bitcoin’s difficulty adjustment happening about every two weeks), resulting in a potentially different target for each block.

  2. While seemingly achieving its goal in practice, there is no formal analysis to back this proposal up.

  3. This paper provides the first formal cryptographic analysis of Bitcoin Cash’s target recalculation functions against all possible adversaries.

  4. It follows the analytical approach developed in the Bitcoin backbone protocol, of first establishing basic properties of the blockchain data structure, from which the properties of a robust transaction ledger (namely, Consistency and Liveness) can be derived.

  5. However, the more active target recalculation mechanism as well as the more pronounced fluctuation of the mining population (due in part to miners’ behavior of switching chains towards achieving higher expected rewards) require new analytical tools.

  6. The analysis is performed in the bounded-delay network model with dynamic participation of miners, of both ASERT and SMA (Bitcoin Cash’s current and former recalculation functions, respectively)

  7. In order to satisfy security (namely, properties satisfied except with negligible probability in the security parameter) considerably larger parameter values should be used with respect to the ones used in practice.

AuthorsJuan Garay* and Yu Shen*,

Affiliations: * Texas A&M University.


1. Paper Title: Low-cost attacks on Ethereum 2.0 by sub-1/3 stakeholders.

Summary: Two dishonest strategies that can be cheaply executed on the Ethereum 2.0 beacon chain, even by validators holding less than one-third of the total stake: malicious chain reorganizations (“reorgs”) and finality delays.

Authors: Michael Neuder*, Daniel J. Moroz*, Rithvik Rao*, and David C. Parkes*,

Affiliations* Harvard University.


1. Paper Title: An Evaluation of Cryptocurrency Payment Channel Networks and Their Privacy Implications.

Summary: An analysis of current PCNs along with their privacy implications.

Authors: Enes Erdin*, Suat Mercan†, and Kemal Akkaya,

Affiliations* University of Central Arkansas and † Florida International University.


1. Paper Title: FPPW: A Fair and Privacy Preserving Watchtower For Bitcoin.

Summary: A new privacy-preserving payment channel with watchtower scheme for Bitcoin, which is fair w.r.t. all channel participants and allows the channel parties to go offline for a long period of time.

Authors: Arash Mirzaei*, Amin Sakzad*, Jiangshan Yu*, and Ron Steinfeld*,

Affiliations* Monash University.


1. Paper Title: BooLigero: Improved Sublinear Zero Knowledge Proofs for Boolean Circuits.

Summary: An improvement to Ligero tailored for Boolean circuits.

Authors: Yaron Gvili*, Sarah Scheffler†, and Mayank Varia†,

Affiliations* Cryptomnium LLC and † Boston University.

2. Paper Title: Cuproof: A Novel Range Proof with Constant Size.

Summary: The scheme of Cuproof would make a range proof to prove that a secret number v ∈ [a, b] without exposing redundant information of v.

Authors: Cong Deng*, Xianghong Tang*, Lin You*, and Gengran Hu*,

AffiliationsHangzhou Dianzi University.


1. Paper Title: Order-Fair Consensus in the Permissionless Setting.

Summary: The main contribution of this paper is to construct fair ordering protocols in the permissionless setting.

Authors: Mahimna Kelkar*, Soubhik Deb†, and Sreeram Kannan†,

Affiliations* Cornell University and † University of Washington.


1. Paper Title: How Elon Musk’s Twitter activity moves cryptocurrency markets.

Summary: This work analyzes to what extent Musk’s Twitter activity affects short-term cryptocurrency returns and volume.

AuthorsLennart Ante*†,

Affiliations: * Blockchain Research Lab and † Universität Hamburg.

Conferences’ Videos:



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